I have just joined this forum in desperation and have been reading with interest the posts regarding overseas use of mobile. I have had my phone since January 2015 and have had several holidays overseas with no service. Each time I have called they say they will reset so it will definitely work next time - but it doesn't. I am expecting a new sim to be delivered today as they think that will be the answer but I don't think I'll risk it again and just change my provider. It's impossible to resolve - each time you phone you get a different excuse - they must know that something is wrong but will not do anything about it. At least I can see I'm not the only one with this problem. Has anyone managed to resolve the problem successfully?